one of the guys I play with runs 155s and on the few times I played on his bike, I never liked the way it felt. his gearing was similar to mine, but felt way harder. I guess that explains why I always beat him on the sprint/joust. I find 165 is just right...
Short cranks?
does anybody on here play with super short cranks? i currently have 175s (way to long) and have found some 150s, but don't know if a 2.5cm difference is gonna hurt my leverage. thoughts?
just wanted to point out that short cranks do not restrict how much torque you can have or how easy you can accelerate. They do have an effect on your gain ratio, a ratio that can be calculated with a sheldon brown aplet, as is pointed out in a later post.
just wanted to point out that short cranks do not restrict how much torque you can have or how easy you can accelerate. They do have an effect on your gain ratio, a ratio that can be calculated with a sheldon brown aplet, as is pointed out in a later post.
Thank you. I have been discussing this with my team, none of which seem to understand/believe that you can get basically the same torque and acceleration despite short cranks. Mike Burrows discusses it in his Bicycle Design book, but I couldnt recall the mechanics clearly enough to present a convincing arguement. Thay all seem to think that short crank = no leverage.
all other things being equal, a shorter crank gives you less leverage. your legs are spinning that much smaller a distance for every rotation, it's a shorter lever. it's not a huge difference, but when you're playing polo fixed you're spinning so much you should notice. the smaller circles make it easier to spin fast and still maintain your form, that's why i've been running 165s (that and pedal strike). gain ratio is basically a measurement of "how easy you can accelerate."
i went through non-drive-side crank arms this weekend, one 172.5, one 170. i'm going to switch to 160s...
i have 140mm truvativ jr. bmx cranks on my polo bike. you dont get as much momentum off the line as you would with longer cranks, but i can make extremely sharp turns without ever having to worry about pedal strike.
I also ride 140's (Origin8 single speed series) with 35-20 fixed and 700's and I'm not sure it would be possible for me to pedal strike with out laying my bike down even with giant metal bmx pedals.
I definitely get less leverage but with my gear ratio it doesn't slow me down too much. Balance is another story, track standing with your feet that close together is definitely a challenge.
http://software.bareknucklebrigade.com/rabbit.applet.html
this handy applet will calculate sheldon brown's "gain ratio." it takes the crank arm length into account.
Columbia, MO
yeah, thanks guys. i think i'll do some 165s instead. 175 is generally fine on a freewheel, but sometimes, i need to pedal through a turn and end up washing out pretty bad.
you might want to look into bmx cranks. They are much better at taking impacts and not ruining the crank arms.
i second this. i've had 160mm bmx cranks for a year now and love'em. i rarely clip my pedal even when pedaling through tight turns. and they'll out last frame
-hero squad * milwaukee, wi-
yah. i "washed out" a few weeks ago and somehow managed to fracture my collar bone.
Plus one for using 165mm cranks. I switched a few months ago.
If you live in MN, IA, MO, WI, IL, MI, IN, KY, and OH why not join the Midwest Club page?
i run 170s and pedal strike rarely. i also have plastic pedals so when i do pedal strike its kind like just hitting a bump very rarely do i foot down from a pedal strike
MKE!
I'm going down to 160s to avoid pedal strike. It's true that plastic pedals take the impact better, even riding fixed, but I'd rather not lose momentum like that if possible. I am gearing down at the same, though, since leverage will be an issue. I like the feel of shorter cranks, because once you get them going, its easy to keep them going.
OGT-COMOPOLO
I play with 170s since it was what was on my polo bike when i got it.
I normally ride with 165's.
I rarely, but occasionally had pedal strike with track pedals. So i swapped to odyssey twisted pedals hoping that would make things a bit easier, but found since they are so wide i was pedal striking more and it was more of a pain, even if when i did pedal strike it wasnt so bad.
since i have switched to clipless (time atac) on my everyday and then my polo bike. havent pedal struck since, due to how narrow the pedal is.
i think that clipless offer a lot of advantages in terms of pedal strike but the reason that people use wide plastic pedals is that the width is an advantage for some. I love the power transfer and how easy it is to find my pedals and my ability to balance. So our only real choice is to go with shorter cranks. I'm running 160's and i have a hard time striking these days.
I had some 155mm for a long time, mainly because of pedal overlap and "fixed gear issues", after using freewheel for 5 month now I need longer crank arms and I'm turning to 170mm
i run a 145mm SINZ BMX crank the ratio is 39 to 24 i definitely like the no pedal strike to ground really can turn sharp with it being fixed. I have no problem with sprints or momentum & would recommend it.
I ride an 1/8 inch scrambler 26 inch wheels, sinz 150mm bmx cranks and my gear is 34-23. This is an awesome setup for fixed gear polo bike. This. Bike is quick and is very easy to stop and start. Wide bmx pedals and holdfast straps . This gives me more surfaace area for my feet, it in turn gives me better balance. Zero pedal strike.
I use 145mm (great stuff!!) .... and never impacted on the floor :)
hard to comment on what size of cranks you should use if you don't tell anyone how tall you are....What is your inseam? Crank length isn't as simple as choosing what gearing you want...(well maybe it is actually, but you have to take the other pulley into account too...your leg) So if you want my 2 cents as a framebuilder you need to give more info. If you're 5'2" then 150s would be great, if you're 6'7" then 150s would be ridiculous. If it's pedal strike you're worried about, short cranks will help that, but at the expense of your optimal power stroke. You'd be better off to find cranks that are suited to your size, and then if pedal strike is a concern you need to find a frame with a higher bottom bracket.
I agree with this and I want to add that play style is a factor too. For example, a low bottom bracket is really great for low speed stability. So then you've got the pedal strike trade but maybe a player likes firing chill stable accurate lasers from half court more than accelerating through turns ...
A custom frame is definitely the way to go when you can anyway. Because you can tell Justin or any builder about your style and that will go into the frame just like your torso and appendage measurements will.
Some things you can do to change real bottom bracket height a little bit for a frame you already have:
- experiment with tire diameter - try both extremes that will fit on the bike
- Narrower pedals - less strike with the same cranks (I do this because I'm more comfortable not hitting the pavement than I am with wide platforms)
- get an eccentric axle rear hub (designed for 1 speed with vertical dropouts) and try it in up vs. down with your track ends (horizontal don't dropouts).
And save up for that new frame-in-4-sizes, or a custom while you generate a personal opinion with this stuff!
Devin
Another thing one might consider along with playing style, pedal length, is the Q-factor of the cranks. -Road/track cranks + spd's = longer cranks & lower BB. -BMX / MTB cranks + platform pedals needs shorter cranks / higher BB.
ATMO inseam length is not such an issue for polo as the bikes aren't ridden for long distances in one position, just making power like road bikes are. Shorter cranks are good for the knees of people with shorter legs as the knee doesn't have to flex through such a wide variation in angle. Trying to generate power through a bent knee for a long time ends up hurting. For polo (as it is for MTB) torque is key for rapid acceleration (gain ratio). This mean cranks for polo should be as long as is sensible to avoid pedal strike / toe-overlap.
150s are going to be a huge pain. I have found that switching from 170's to 160's that i'm a bit slower now. I'm probably going to gear down because i really like the clearance on the 160's. Also, if you ride fix then 160's or below is going be really hard to leverage.